Circuit breakers are used to protect equipment from overcurrent situations caused, for example, by short circuits or ground faults in or near such equipment. In the event an overcurrent condition occurs, electrical contacts within the circuit breaker will open, stopping the flow of electrical current through the circuit breaker to the equipment. Circuit breakers may be designed for high quiescent currents and high withstand currents. To maintain a high withstand current rating, the contacts must be clamped closed at the current withstand rating. On the other hand, the short circuit let-through current must be capable of opening the contacts quickly at short circuit. The drawback of having the contacts clamped closed is that the contacts may not be able to open quickly at the short circuit current level.
The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by a magnetic release system for a circuit breaker. In an exemplary embodiment of the invention, a magnetic release system for a circuit breaker includes a contact structure; a strap configured to conduct a first level of electrical current and a second level of electrical current; a u-shaped collar having a pole face, the u-shaped collar disposed around the strap; a release lever disposed proximate the pole face, the release lever rotatably mounted on the strap; wherein the release lever is releasably engaged with the contact structure; and wherein the release lever prevents movement of the contact structure at the first level of electrical current and releases the contact structure at the second level of electrical current.
In an alternative embodiment, a circuit breaker includes: a first contact structure in contact with a second contact structure; and a magnetic release system arranged to separate the first contact structure and the second contact structure, the magnetic release system including: a strap configured to conduct a first level of electrical current and a second level of electrical current, a u-shaped collar having a pole face, the u-shaped collar disposed around the strap, a release lever disposed proximate the first pole face, the release lever rotatably mounted on the strap, wherein the release lever is releasably engaged with the second contact structure, and wherein the release lever prevents movement of the second contact structure at the first level of electrical current and releases the second contact structure at the second level of electrical current.